RM-12989, Editing memberships, contributions or event registrations in multiple tabs replaces data

gistfile1.php

diff --git a/CRM/Contribute/Form/AbstractEditPayment.php b/CRM/Contribute/Form/AbstractEditPayment.php
index 7fb7a90..162c37d 100644
--- a/CRM/Contribute/Form/AbstractEditPayment.php
+++ b/CRM/Contribute/Form/AbstractEditPayment.php
@@ -209,7 +209,15 @@ class CRM_Contribute_Form_AbstractEditPayment extends CRM_Contact_Form_Task {
    * Pre process function with common actions.
    */
   public function preProcess() {
-    $this->_contactID = CRM_Utils_Request::retrieve('cid', 'Positive', $this);
+    //CRM-12989, allocate entity and contact id, retrieved from controller->_entryURL rather than REQUEST to
+    //resolve overriding of values due to opening multiple tabs although a hackish fix
+    if ($this->controller->_entryURL &&
+      ($queryParams = str_replace('&', '&', parse_url($this->controller->_entryURL, PHP_URL_QUERY)))
+    ) {
+      parse_str($queryParams, $urlParts);
+      $this->_contactID = CRM_Utils_Array::value('cid', $urlParts);
+      $this->_id = CRM_Utils_Array::value('id', $urlParts);
+    }
     $this->assign('contactID', $this->_contactID);
     CRM_Core_Resources::singleton()->addVars('coreForm', array('contact_id' => (int) $this->_contactID));
     $this->_action = CRM_Utils_Request::retrieve('action', 'String', $this, FALSE, 'add');
diff --git a/CRM/Contribute/Form/Contribution.php b/CRM/Contribute/Form/Contribution.php
index abe7be6..85e8b81 100644
--- a/CRM/Contribute/Form/Contribution.php
+++ b/CRM/Contribute/Form/Contribution.php
@@ -228,8 +228,6 @@ class CRM_Contribute_Form_Contribution extends CRM_Contribute_Form_AbstractEditP
 
     $this->assign('action', $this->_action);
 
-    // Get the contribution id if update
-    $this->_id = CRM_Utils_Request::retrieve('id', 'Positive', $this);
     if (!empty($this->_id)) {
       $this->assign('contribID', $this->_id);
     }
diff --git a/CRM/Member/Form.php b/CRM/Member/Form.php
index ca06acb..e4faf3f 100644
--- a/CRM/Member/Form.php
+++ b/CRM/Member/Form.php
@@ -99,7 +99,7 @@ class CRM_Member_Form extends CRM_Contribute_Form_AbstractEditPayment {
     parent::preProcess();
     $params = array();
     $params['context'] = CRM_Utils_Request::retrieve('context', 'String', $this, FALSE, 'membership');
-    $params['id'] = CRM_Utils_Request::retrieve('id', 'Positive', $this);
+    $params['id'] = $this->_id;
     $params['mode'] = CRM_Utils_Request::retrieve('mode', 'String', $this);
 
     $this->setContextVariables($params);